This invention generally relates to vehicle navigation systems and more particularly to a vehicle navigation system that includes the ability to update a chosen route strategy given current road or traffic conditions, for example.
Navigation systems are becoming increasingly popular on passenger vehicles. Typical navigation systems utilize a satellite-based global positioning system and a prestored map database that includes a number of established reference points. A variety of topologies and navigational algorithms are utilized to provide a navigation solution or route strategy that guides a vehicle operator to a chosen destination. The navigation system determines a current position of the vehicle based upon signals received from the satellite-based global positioning system. The position information and the chosen destination are then utilized to determine a route strategy to reach the desired destination based upon the prestored map database.
Although navigation systems are becoming more popular and have proven useful, they are not without limitations. One major shortcoming is that prestored map databases become at least partially obsolete very soon after they are distributed. The primary factors that render a map database effectively obsolete include road construction, weather conditions, accidents and changes in the locations of roads or permissible travel patterns along roads. An attempt at addressing these problems includes providing periodic updates to map databases. These updates, however, are prohibitively expensive and insufficient under many circumstances because it is impossible to predict the location and effect of weather conditions and traffic accidents, for example.
One proposed enhancement has been to utilize cellular communication networks to provide updated travel information. Such systems still have drawbacks including expensive monthly fees for cellular network access and overcrowded communications associated with limited cellular communication resources.
This invention addresses the need for having a navigation system that provides an optimum route strategy that takes into account road conditions on a real time basis. This invention provides greater flexibility and effectiveness for vehicle navigation systems.
In general terms this invention is a vehicle navigation system that includes route guidance updating features that are useful on a real time basis.
A navigation system designed according to this invention includes several basic components. An input device allows a driver to input a desired destination or location. A receiver is supported on the vehicle that receives signals that indicate a current position of the vehicle. A memory module is supported on the vehicle that contains a prestored map database that includes a plurality of known location reference points. An update module receives at least one travel advisory signal that indicates a current traffic situation that is not accounted for in the prestored database. An electronic controller supported on the vehicle communicates with the input module, the receiver, the memory module and the update module to generate a route guidance strategy to guide the driver from a current position to the desired destination. Additionally the electronic controller utilizes further travel advisory signals and determine whether the current traffic situation affects previously generated route guidance strategy. Whenever appropriate, the electronic controller automatically generates an updated route guidance strategy taking into account the current traffic situation.
A navigation system designed according to this invention preferably includes a transmitter supported on the vehicle that transmits a beacon signal indicating that the vehicle is in a condition or position that presents a potential traffic hazard for other vehicles. The transmitter beacon signal preferably is generated whenever the driver activates the hazard lights of the vehicle. Alternatively, the beacon signal is automatically generated by the system electronic controller when certain preselected conditions are satisfied. The beacon signal from one vehicle is one type of travel advisory signal that is received by navigation systems designed according to this invention and placed in other vehicles, which utilize that information to generate updated route guidance strategies.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.